Fuse plug



April 13, 1926. 1,580,996 L. D CHRISTIE Filed August 15, 1924 E O A lawame/s1- 5 v BY M a Patented Apr. 13, 1925.

UNITED STATES 11,580,996 PATENT OFFICE.

LEWIS I). CHRISTIE, OF TRUMB'ULL, CONNECTICUT, ASSIGNOR TO THE BRYANTELECTRIC COMPANY, OF BRIDGEPOET, CONNECTICUT, A CORPORATION OF CON-NECTICUT.

FUSE PLUG.

Application filed August 15, 1924. seen No. 732,224.

To all whom it may concern:

Be it known that I, Lnwis D. CHRISTIE, a citizen of the United States ofAmerica, residing at Trumbull, in the county of F airfield and State ofConnecticut, have invented certain new and useful Improvements in FusePlugs, of which the following is a specification.

My invention relates to fuse plugs and the object of my invention is tosimplify and improve both its construction and the method ofmanufacture.

In the accompanying drawings- Fig. 1 is a vertical section through afuse plug in which my invention is embodied in one form.

Figs. 2, 3 and 4c are similar views of the plug in the course ofmanufacture.

My invention relates primarily to the center contact of the plug, but Ihave shown a complete structure of more or less standard type comprisinga thimble body of in-.

sulation, with screw 'shellcontact 16, and metal cap 17, which holds inposition the disc 18 of isinglass or the like through which, and thecentral aperture 19 in the cap 17, the condition of the fuse strip 20may be observed. One end of the strip 20 is carried as usual over thetop of the barrier 21 into the side well 22 of the body 15 and is theresecured and electrically connected to the screw shell 16, as by solder23. A top iill 24lof cement may be added, if desired. The opposite endof the fuse strip is connected to the center contact 25 of the plug inthe improved fashion which constitutes my invention.

The center contact assembly is graphically shown in Figs. 2 to linclusive. As indicated in Fig. 2 the bottom of the body 15 is aperturedto form a passage 26. The center contact end of the strip is passed intothis aperture and is there engaged by a pellet 27 of any appropriateconducting material which is readily deformed by pressure, for example,a malleable metal such as lead, or suitable alloy. To facilitate theseating of the pellet at the inner end of passage 26, the lower interiorwall 28 of the body may be coned or otherwise shaped to lead the pelletto position when freely dropped into the upper end of the chamber of thebody 15. A tool 29 is introduced through the chamber of the body 15While the latter is held on a suitable support 30,

then deforms the pellet 27 and the end of the fuse strip which overliesthe inner edge 31 of the aperture 26, thus forcing the material of thepellet down into the passage 26 and embedding the end of the fuse striptherein. At the same time, the inner portion of the pellet isspread toform a mushroom head which serves not only as a gas check but also as aretainer to prevent the removal of the centercontact from the body. Thecenter contact 25 is provided with a pointed shank 32, after the fashionof a thumb tack, and is now driven by tool 33 upward through the passage26. The shank penetrates the pellet, still backed by the tool 29, and isoffset by the latter, thus riveting or clinching the contact in positionand to the pellet, while at the same time establishing good electricalconnection with the fuse strip 20.

When the center contact assembly has been thus completed, the free endof the strip may be inserted in the well 22 and soldered, or any otherappropriate connection to the screw shell 16 may be efiected.

Various modifications in detail of both structure and method willreadily occur to those dealing with the problem. For example the pellet27 may be molded on the end of the strip 20 before the latter isinserted in position. The shape of the pellet and of the strip, and ofthe center contact may all be varied within the limits of my claim ofinvention.

The invention provides a cheap and easy center contact construction andassembly which is good electrically and eliminates the solderedconnection between the center contact and fuse strip which is nowextensively used in plugs of this character.

I claim as my invention:

1. A fuse plug comprising a center contact provided with a pointedshank, a fuse strip, and a soft metal engaging one end of the fuse stripand penetrated by the shank of the center contact.

2. A fuse plug comprising a fuse strip, soft metal engaging one end ofthe fuse strip, and a center contact having a pointed shank whichpenetrates and is olf-set in said metal to rivet said parts together ingood electrical connection.

3. A fuse plug comprising an insulating body pierced by a passage at itsentering end, a fuse strip, a body of soft metal engaging the end ofsaid fuse strip, together with a center contact having a pointed shankentering said passage and penetrating said soft metal and serving tohold said center contact in position in good electrical connection withthe fuse strip.

4:. The method of manufacturing fuse plugs which comprises engaging theend of a fuse strip with a pellet of soft metal within the" chamber ofthe fuse plug body and forcing "the shank of a center contact through anaperture in the plug body and into said soft metal to secure the contactin position on the body in good electrical'connection with the fusestrip.

5. The method of manufacturing fuse plugs which comprises engaging theend of a fus'e strip with a pellet of soft metal within the chamber of afuse plug body, and forcing thefshank of the center contact: through anaperture in the plug body into offset connection with said soft metal tosecure the contact in position in good electrical connection with thefuse strip.

6. The method of manufacturing fuse plugs which comprises the step ofdeforming the shank of the center contact in a body of soft metalelectrically connected to an end of the fuse strip.

7 A fuse plug comprising a center contact provided with a shank, a fusestrip, and a mush'roo ned body of soft metal engaging the fuse strip andpenetrated by the shank of the center contact.

8. A fuse plug comprising a. one-piece insulating body apertured at itsentering end, a screw shell side contact secured to said body, a fusestrip electrically connected to said screw shell and ei igaged at saidaper ture by soft metal, together with a center contact pin penetratingand deformed in said soft metal to establish electrical con nection withthe fuse strip and to maintain the center contact in position.

In testimony whereof I have signed my name to this specification.

LEWIS D. CHRISTIE.

